diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/bio.c | 17 | ||||
| -rw-r--r-- | block/blk-cgroup.c | 23 | ||||
| -rw-r--r-- | block/blk-iolatency.c | 14 | ||||
| -rw-r--r-- | block/blk-throttle.c | 4 |
4 files changed, 29 insertions, 29 deletions
diff --git a/block/bio.c b/block/bio.c index 346a7f5cb2dd..5c9828524adc 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2009,21 +2009,24 @@ int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) EXPORT_SYMBOL_GPL(bio_associate_blkcg); /** - * bio_associate_blkg - associate a bio with the specified blkg + * bio_associate_blkg - associate a bio with the a blkg * @bio: target bio * @blkg: the blkg to associate * - * Associate @bio with the blkg specified by @blkg. This is the queue specific - * blkcg information associated with the @bio, a reference will be taken on the - * @blkg and will be freed when the bio is freed. + * This tries to associate @bio with the specified @blkg. Association failure + * is handled by walking up the blkg tree. Therefore, the blkg associated can + * be anything between @blkg and the root_blkg. This situation only happens + * when a cgroup is dying and then the remaining bios will spill to the closest + * alive blkg. + * + * A reference will be taken on the @blkg and will be released when @bio is + * freed. */ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) { if (unlikely(bio->bi_blkg)) return -EBUSY; - if (!blkg_try_get(blkg)) - return -ENODEV; - bio->bi_blkg = blkg; + bio->bi_blkg = blkg_try_get_closest(blkg); return 0; } diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index b421a9457e05..120f2e2835fb 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -258,9 +258,8 @@ err_free_blkg: * that all non-root blkg's have access to the parent blkg. This function * should be called under RCU read lock and @q->queue_lock. * - * Returns pointer to the looked up or created blkg on success, ERR_PTR() - * value on error. If @q is dead, returns ERR_PTR(-EINVAL). If @q is not - * dead and bypassing, returns ERR_PTR(-EBUSY). + * Returns the blkg or the closest blkg if blkg_create() fails as it walks + * down from root. */ struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, struct request_queue *q) @@ -276,19 +275,29 @@ struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, /* * Create blkgs walking down from blkcg_root to @blkcg, so that all - * non-root blkgs have access to their parents. + * non-root blkgs have access to their parents. Returns the closest + * blkg to the intended blkg should blkg_create() fail. */ while (true) { struct blkcg *pos = blkcg; struct blkcg *parent = blkcg_parent(blkcg); - - while (parent && !__blkg_lookup(parent, q, false)) { + struct blkcg_gq *ret_blkg = q->root_blkg; + + while (parent) { + blkg = __blkg_lookup(parent, q, false); + if (blkg) { + /* remember closest blkg */ + ret_blkg = blkg; + break; + } pos = parent; parent = blkcg_parent(parent); } blkg = blkg_create(pos, q, NULL); - if (pos == blkcg || IS_ERR(blkg)) + if (IS_ERR(blkg)) + return ret_blkg; + if (pos == blkcg) return blkg; } } diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index e6f68f15dee9..46e86c34cf79 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -483,21 +483,11 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio) rcu_read_lock(); bio_associate_blkcg(bio, NULL); blkcg = bio_blkcg(bio); - blkg = blkg_lookup(blkcg, q); - if (unlikely(!blkg)) { - spin_lock_irq(&q->queue_lock); - blkg = __blkg_lookup_create(blkcg, q); - if (IS_ERR(blkg)) - blkg = NULL; - spin_unlock_irq(&q->queue_lock); - } - if (!blkg) - goto out; - + blkg = blkg_lookup_create(blkcg, q); bio_issue_init(&bio->bi_issue, bio_sectors(bio)); bio_associate_blkg(bio, blkg); -out: rcu_read_unlock(); + while (blkg && blkg->parent) { struct iolatency_grp *iolat = blkg_to_lat(blkg); if (!iolat) { diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8f0a104770ee..d648d6720f46 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2118,9 +2118,7 @@ static inline void throtl_update_latency_buckets(struct throtl_data *td) static void blk_throtl_assoc_bio(struct throtl_grp *tg, struct bio *bio) { #ifdef CONFIG_BLK_DEV_THROTTLING_LOW - /* fallback to root_blkg if we fail to get a blkg ref */ - if (bio->bi_css && (bio_associate_blkg(bio, tg_to_blkg(tg)) == -ENODEV)) - bio_associate_blkg(bio, bio->bi_disk->queue->root_blkg); + bio_associate_blkg(bio, tg_to_blkg(tg)); bio_issue_init(&bio->bi_issue, bio_sectors(bio)); #endif } |